Impact of left ventricular hypertrophy on impaired coronary microvascular dysfunction

The role of left ventricular hypertrophy measured by echocardiography in screening patients with ischaemia with non-obstructive coronary arteries: a cross-sectional study

Many patients with ischaemia with non-obstructive coronary arteries (INOCA) have a poor prognosis. This study aims to explore the diagnostic value of left ventricular hypertrophy (LVH)-related ultrasound parameters in INOCA patients. The study group consisted of 258 patients with INOCA in this retrospective cross-sectional study, and these patients were free of obstructive coronary artery disease, previous revascularization, atrial fibrillation, ejection fraction < 50%, major distortions of left ventricular geometry, suspected non-ischaemic causes. Control individuals were matched 1:1 with study group according to age, sex, cardiovascular risk factors, and time of hospital stay. According to left ventricular mass index (LVMI) and relative wall thickness, left ventricular geometry was composed of concentric hypertrophy, eccentric hypertrophy, concentric remodeling and normal geometry. LVH-related parameters, left ventricular geometry, demographic characteristics, laboratory parameters and other echocardiographic indicators were compared between the two groups. Subgroup analysis was performed based on sex. LVMI in the study group was higher than that in the control group (86.86 ± 18.83 g/m2 vs 82.25 ± 14.29 g/m2, P = 0.008). The ratio of LVH was higher in the study group (20.16% vs 10.85%, P = 0.006). After subgroup analysis based on sex, LVMI differences (85.77 ± 18.30 g/m2 vs 81.59 ± 14.64 g/m2, P = 0.014) and the ratio of LVH differences (25.00% vs 14.77%, P = 0.027) still existed in females between the two groups. There was no difference in the constituent ratio of left ventricular geometry between the two groups (P = 0.157). Sex-based subgroup analysis showed no difference in the constituent ratio of left ventricular geometry between the two groups in females (P = 0.242). The degree of LVH in the study group was higher than that in the control group, suggesting that LVH may play an important role in the occurrence and development of INOCA. Moreover, LVH-related ultrasound parameters may be of higher diagnostic value for female INOCA patients than for male INOCA patients.

New insights from the MESA study: increased high-sensitivity troponins as a cardiovascular risk factor

The most recent high-sensitivity assays for troponins I and T (hs-TnI and hs-TnT) have made it possible to detect blood concentrations up to 10 times lower than previous assays, making troponins detectable even in asymptomatic subjects without manifest cardiovascular disease. For this reason, hs-Tn, initially introduced as markers of myocardial damage in an acute setting, have also become possible markers of subclinical myocardial damage in baseline conditions. In fact, recent evidence suggests that hs-TnT and hs-TnI predict the risk of future cardiovascular events also in the context of primary prevention, and offer incremental information when added to current risk stratification models. The different association highlighted with different outcome measures, such as coronary heart disease, atherosclerotic cardiovascular disease, heart failure, and death from all causes, seems to indicate that the risk observed in asymptomatic subjects with high levels of hs-Tn is an expression of subclinical damage secondary to multiple pathophysiological mechanisms, and not only to atherothrombosis. However, the ability of hs-TnT and hs-TnI (until now used interchangeably), to provide differential predictive information, and not redundant with respect to more traditional factors, remains to be definitively clarified, both for the purpose of predicting specific outcomes and for the implementation of specific preventive strategies. To date, evidences available allow us to hypothesize their role more as markers than as risk factors.

Coronary Microvascular Dysfunction

Many patients with chest pain undergoing coronary angiography do not show significant obstructive coronary lesions. A substantial proportion of these patients have abnormalities in the function and structure of coronary microcirculation due to endothelial and smooth muscle cell dysfunction. The coronary microcirculation has a fundamental role in the regulation of coronary blood flow in response to cardiac oxygen requirements. Impairment of this mechanism, defined as coronary microvascular dysfunction (CMD), carries an increased risk of adverse cardiovascular clinical outcomes. Coronary endothelial dysfunction accounts for approximately two-thirds of clinical conditions presenting with symptoms and signs of myocardial ischemia without obstructive coronary disease, termed "ischemia with non-obstructive coronary artery disease" (INOCA) and for a small proportion of "myocardial infarction with non-obstructive coronary artery disease" (MINOCA). More frequently, the clinical presentation of INOCA is microvascular angina due to CMD, while some patients present vasospastic angina due to epicardial spasm, and mixed epicardial and microvascular forms. CMD may be associated with focal and diffuse epicardial coronary atherosclerosis, which may reinforce each other. Both INOCA and MINOCA are more common in females. Clinical classification of CMD includes the association with conditions in which atherosclerosis has limited relevance, with non-obstructive atherosclerosis, and with obstructive atherosclerosis. Several studies already exist which support the evidence that CMD is part of systemic microvascular disease involving multiple organs, such as brain and kidney. Moreover, CMD is strongly associated with the development of heart failure with preserved ejection fraction (HFpEF), diabetes, hypertensive heart disease, and also chronic inflammatory and autoimmune diseases. Since coronary microcirculation is not visible on invasive angiography or computed tomographic coronary angiography (CTCA), the diagnosis of CMD is usually based on functional assessment of microcirculation, which can be performed by both invasive and non-invasive methods, including the assessment of delayed flow of contrast during angiography, measurement of coronary flow reserve (CFR) and index of microvascular resistance (IMR), evaluation of angina induced by intracoronary acetylcholine infusion, and assessment of myocardial perfusion by positron emission tomography (PET) and magnetic resonance (CMR).

Impact of Chronic Kidney Disease on Outcomes After Percutaneous Coronary Intervention for Chronic Total Occlusions (from the Japanese Multicenter Registry)

The impact of chronic kidney disease (CKD) and potential pharmacologic intervention on clinical outcomes after percutaneous coronary intervention (PCI) for chronic total occlusions (CTOs) remains unknown. A total of 1,463 patients underwent successful CTO-PCI between August 2004 and December 2014. Major adverse cardiovascular events (MACE) defined as the composite of all-cause death, myocardial infarction and target lesion revascularization, cardiac death, and stent thrombosis were compared between patients with and without CKD (555 and 908 patients, respectively). The results demonstrated higher risks of MACE (log-rank p = 0.015), all-cause death (log-rank p <0.001), and cardiac death (log-rank p <0.001) in the CKD group compared with the non-CKD group. Multivariable analyses demonstrated that CKD was an independent predictor for MACE (hazard ratio 1.23, 95% confidence interval 1.02 to 1.47, p = 0.03). With regard to pharmacotherapy, statin use was associated with significantly lower rates of MACE in the CKD group (log-rank p = 0.003). In conclusion, the presence of CKD would be an important predictor of long-term clinical outcomes in patients who underwent CTO-PCI, and use of statin may influence in reducing the adverse clinical outcomes.

The emerging role of Cardiovascular Magnetic Resonance in the evaluation of hypertensive heart disease

BACKGROUND

Arterial hypertension is the commonest cause of cardiovascular death. It may lead to hypertensive heart disease (HHD), including heart failure (HF), ischemic heart disease (IHD) and left ventricular hypertrophy (LVH).

MAIN BODY

According to the 2007 ESH/ESC guidelines, the recommended imaging technique is echocardiography (echo), when a more sensitive detection of LVH than that provided by ECG, is needed. Cardiovascular Magnetic Resonance (CMR), a non-invasive, non-radiating technique, offers the following advantages, beyond echo: a) more reliable and reproducible measurements of cardiac parameters such as volumes, ejection fraction and cardiac mass b) more accurate differentiation of LVH etiology by providing information about tissue characterisation c) more accurate evaluation of myocardial ischemia, specifically if small vessels disease is present d) technique of choice for diagnosis of renovascular, aortic tree/branches lesions and quantification of aortic valve regurgitation e) technique of choice for treatment evaluation in clinical trials. The superiority of CMR against echocardiography in terms of reproducibility, operator independency, unrestricted field of view and capability of tissue characterization makes the technique ideal for evaluation of heart, quantification of aortic valve regurgitation, aorta and aortic branches.

CONCLUSIONS

CMR has a great potential in early diagnosis, risk stratification and treatment follow up of HHD. However, an international consensus about CMR in HHD, taking under consideration the cost-benefit ratio, expertise and availability, is still warranted.

Troponin in Cardiovascular Disease Prevention: Updates and Future Direction

Cardiac troponin has been well described as the preferred biomarker for diagnosis of myocardial infarction due to the high sensitivity and specificity for myocardial injury. Numerous other conditions apart from acute coronary syndrome can also lead to small elevations in troponin levels. However, the use of cTn as prognostic biomarker for the primary assessment of cardiovascular risk in asymptomatic patient has only recently been described. And with the development of newer generations of high-sensitivity cardiac troponin assays that can detect 10-fold lower concentrations of troponin, the potential value cTn in the prevention and management of asymptomatic cardiovascular disease has come to the fore. This review provides an overview of the transition of cardiac troponin as a marker of acute myocardial injury to one that detects sub-clinical injury. Evidence continues to show that high-sensitivity troponin is emerging as one of the most powerful prognostic biomarkers for the assessment of cardiovascular risk in the general population.